The Pd(II)-acetate catalyzed ring closure of halogenated diphenyl ethers and benzophenones is being utilized to synthesize halogenated dibenzofurans and fluorenones. Such polyhalogenated aromatic compounds are of current toxicological interest as potential persistent environmental agents. Dibenzofurans synthesized inclue two hexas (1,2,4,6,8,9 and 2,3,4,6,7,8), one tetra (2,3,7,8), one tri (2,3,8) and one disubstituted (3,7). 2,3,7,8-Tetrachlorofluorenone was also synthesized.